Process of making a lamellated wood product

ABSTRACT

A process for making a lamellated wood product is disclosed. The process has the following steps:  
     a) providing wood slats of generally uniform thickness;  
     b) edge-bonding the wood slats to form a large panel of a predetermined width;  
     c) cutting lengthwise the panel of step b) into a plurality of small panels of substantially identical width;  
     d) face-bonding a number of the small panels to form a lamellated beam having a thickness equal to the width of the small panels and a width equal to the product obtained by multiplying said number of small panels with the thickness of the same;  
     e) cutting lengthwise and thicknesswise the lamellated beam into a plurality of small beams having a width identical to the width of the small panels;  
     f) cutting lengthwise and thicknesswise the small beams into a plurality of lamellated wood product of desired dimensions.  
     The lamellated wood product produced thereof has superior dimensional stability and improved mechanical properties.

FIELD OF THE INVENTION

[0001] The present invention relates generally to the field of wood.More particularly, the present invention relates to a process for makinga lamellated wood product and the lamellated wood product producedthereby.

BACKGROUND OF THE INVENTION

[0002] The field of glued laminated or lamellated wood has producedlamellated wood products that are reliable, dimensionally stable andlong lasting. These lamellated wood products are known to absorb shocksthat would normally break or rupture other material, such asconventional wood products.

[0003] Once, old growth forests provided most of the lumber used in thelamellated wood industry, but these old forests have now largely beencut.

[0004] Today, most of the lumber produced is from much smaller treesobtained from second growth forests and, increasingly, from northernforests or even from plantation forests. The diameter of these trees issmaller than the diameter of the trees harvested from the old forests,and consequently, the lamellated wood products produced therefrom havesmaller dimensions and unfortunately, have lower grades than thoseproduced in the past. Therefore, there is a need for methods that willprovide a lamellated wood product showing improved mechanicalproperties.

[0005] Known in the prior art, there is U.S. Pat. No. 5,881,786 in thename of WILDERMAN ET AL. Wilderman discloses a method of making alamellated wood product using slats from roundwood logs havingend-to-end sweep.

[0006] Even though the processes of making a lamellated wood productknown in the art have resulted in the advancement within the presentfield, there is still a need for a process of making a lamellated woodproduct that will provide a superior dimensional stability and improvedmechanical properties than those produced by processes known to thisdate.

SUMMARY OF THE INVENTION

[0007] It is therefore an object of the present invention to provide aprocess for making a lamellated wood product that will fulfil the abovementioned need.

[0008] In accordance with the invention, that object is achieved with aprocess for making a lamellated wood product comprising the steps of:

[0009] a) providing wood slats of generally uniform thickness;

[0010] b) edge-bonding the wood slats to form a large panel of apredetermined width;

[0011] c) cutting lengthwise the panel of step b) into a plurality ofsmall panels of substantially identical width;

[0012] d) face-bonding a number of the small panels to form a lamellatedbeam having a thickness equal to the width of the small panels and awidth equal to the product obtained by multiplying said number of smallpanels with the thickness of the same;

[0013] e) cutting lengthwise and thicknesswise the lamellated beam intoa plurality of small beams having a width identical to the width of thesmall panels;

[0014] f) cutting lengthwise and thicknesswise the small beams into aplurality of lamellated wood product of desired dimensions.

[0015] The present invention also provides a process for making alamellated wood product comprising the steps of:

[0016] a) providing wood slats of generally uniform thickness;

[0017] b) edge-bonding the wood slats to form panels of a predeterminedsubstantially identical width;

[0018] c) face-bonding the panels to form a lamellated beam with aplurality of lamellation planes;

[0019] d) cutting the lamellated beam along an axis parallel to thelamellation planes to form small beams;

[0020] e) cutting the small beams along at least one axis perpendicularto the lamellation planes to form a lamellated wood product of desireddimensions.

[0021] The present invention also relates to a lamellated wood productobtained by any of the processes as described above.

[0022] The process according to the present invention offers arelatively simple solution for the mass production of a lamellated woodproduct showing excellent and uniform mechanical properties. It alsoallows the sawn timbers to be recycled and the production of wood chipsto be reduced.

[0023] Advantageously, apart from showing excellent and uniformmechanical properties throughout the product, the final wood productobtained by a process according to the present invention shows asuperior dimensional stability over those known in the art. It isbelieved that this is mainly due to the fact that the final wood productis obtained by cutting lenghtwise the intermediate lamellated beamformed during the process along two different axes thereby allowing abetter distribution of the internal forces therein, which in turn ismainly due to the fact that the microstructure, that is to say thedistribution of the fibers, of the final product is more uniform.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention and its advantages will be more easilyunderstood after reading the following non-restrictive description of apreferred embodiment thereof, made with reference to the followingdrawings wherein:

[0025]FIGS. 1A to 1I schematically represent the general steps of makinga lamellated wood product according to a preferred embodiment of theinvention, and wherein FIG. 1A is a perspective view of one slat; FIG.1B is a perspective view showing the steps of edge-bonding slats of FIG.1A to form a large panel; FIG. 1C is a perspective view showing thesteps of cutting lenghtwise the large panel of FIG. 1B to form smallerpanels; FIG. 1D is a perspective view of one small panel; FIG. 1E is aperspective view of a large beam obtained by face-bonding a plurality ofsmall panels of FIG. 1D; FIG. 1F is a perspective view of the large beamof FIG. 1E after being rotated from an angle of 90°; FIG. 1G is aperspective view showing the steps of cutting lenghtwise the large beamof FIG. 1F in order to obtain small beams; FIG. 1H is a perspective viewshowing the steps of cutting lenghtwise one small beam to formlamellated wood products; and FIG. 1I is a perspective view of alamellated wood product of desired dimensions.

[0026]FIGS. 2A to 2C schematically represent the step of end-jointingsmall lamellas of wood to form a longer slat used in the processaccording to a preferred embodiment of the invention, and wherein FIG.2A is a perspective view of one lamella, FIG. 2B is a perspective viewof two lamellas prior being end-jointed; and FIG. 2C is a perspectiveview of a slat of wood obtained by end-jointing the lamellas.

[0027]FIGS. 3A and 3B are schematic views showing the steps ofedge-bonding the slats of FIG. 2C to form a large panel (FIG. 3A) andthe steps of cutting lenghthwise the large panel to form smaller panels(FIG. 3B).

[0028]FIG. 4 is a schematic perspective view illustrating the step ofend-jointing two panels as the one shown in FIG. 3B.

[0029]FIG. 5 is a schematic perspective view showing the step offace-bonding a plurality of panels as the one shown in FIG. 3B to obtaina large beam.

[0030]FIGS. 6A and 6B are schematic perspective views of the beam ofFIG. 5 after being rotated from an angle of 90° (FIG. 6A) and showingthe step of cutting lengthwise the same to obtain smaller beams (FIG.6B).

DESCRIPTION OF A PREFERRED EMBODIMENT

[0031] The wood product obtained with the process according to thepresent invention is obtained by using at first relatively small piecesof wood that are first assembled by edge-bonding and then byface-bonding to be thereafter cut lengthwise along two perpendicularaxes in order to eliminate, or at least greatly reduce, the internalstresses of the final wood product and thus greatly improving thestability of the same.

[0032] FIGS. 1 to 6 are schematically illustrating the differentconsecutive steps of a process for making a lamellated wood product (10)according to the present invention. Generally described the processcomprises the following steps:

[0033] a) providing wood slats (12) of generally uniform thickness (t),as shown in FIG. 1A;

[0034] b) edge-bonding the wood slats (12) of step a) to form a largepanel (16) of a predetermined width, as shown in FIG. 1B;

[0035] c) cutting lengthwise the large panel (16) obtained in step b)into a plurality of smaller panels (18) of substantially identical width(w), as shown in FIG. 1C where, in order not to overload the figure,only one of such smaller panel (18) is illustrated in FIG. 1D; andoptionally end-jointing the panels (18) so obtained to produce longerpanels, as shown in FIG. 4;

[0036] d) referring now to FIG. 1E, a given number of the small panels(18) obtained in step c) are face-bonded to form a lamellated beam (20).The lamellated beam (20) so obtained has, after having been rotated froma 90° angle and as shown in FIG. 1F, a thickness (t′) equal to the width(w) of the smaller panels (18) and a width (w′) equal to the productobtained by multiplying the number of small panels (18) used in thelamellation process with the thickness (t) of the same;

[0037] e) referring now to FIG. 1G, the lamellated beam (20) obtained instep d) is then cut lengthwise and thicknesswise to obtain a pluralityof small beams (22). The dotted lines in FIG. 1G are indicating thecutting lines in the large beam (20) which will give a plurality ofsmall beams (22);

[0038] f) referring now to FIG. 1H, the small beams (22) so obtained,before being send to the next step of the process for further treatment,are rotated from a 90° angle. In order not to overload the figure, onlyone of such small beams (22) is illustrated in FIG. 1H. As can beappreciated from FIG. 1H, after having been so rotated, the small beams(22) show a width (w′″) identical to the width (w) of the small panels(18) shown in FIG. 1D, and a thickness (t″) which depends on where thelarge beam (20) has been cut lenghtwise. Then, the small beams (22) arecut lengthwise and thicknesswise into a plurality of final lamellatedwood products (10) of desired dimensions. The dotted lines shown in FIG.1H are indicating an example of possible cutting lines in the small beam(22). As can be appreciated, the final product (10) obtained, and whereonly one of such final product is shown in FIG. 1I in order not tooverload the figure, has a width (w″) equal to the thickness (t″) of thesmall beam (22) of FIG. 1H and a thickness (t′″) which depends on wherethe small beam (22) has been cut lenghtwise.

[0039] Each of the above generally described steps will now be describedin more detail.

[0040] As shown in FIGS. 2A to 2C, the wood slats (12) used in theprocess may consist of single pieces of wood having at first the lengthrequired or expected for the final product. However, in most cases theprocess will preferably further comprises, prior to the above describedstep a), the additional steps of providing lamellas (14) of generallyuniform thickness (t) and end-jointing the same to form the wood slats(12) used in step a). For example, if the wood slats (12) are longenough for the expected final product they will be used as such. On theother hand, if they do not have the required length, the wood slats (12)appropriate for the process could be easily obtained by end-jointingsmall lamellas of wood (14) as shown in FIGS. 2B and 2C.

[0041] As apparent for any person skilled in that art, the end-jointingof the lamellas (14) could be performed by jointing planar end surfacesof the lamellas (14) together or, as shown in FIGS. 2A and 2B, byjointing corrugated end surfaces (13) of the lamellas (14), this latterprocess being also called finger jointing.

[0042] Although the dimensions of the wood slats (12) suitable for theprocess are not limited to any particular dimension, their preferabledimension is preferably as follows: a thickness (t) varyingapproximately between 0.75 to 2 inches, a width (w) varyingapproximately between 2 to 6 inches and a length (I) preferably varyingbetween 3 to 20 feet.

[0043] As mentioned before, the next step of the process, which isillustrated in FIG. 1B and in better details in FIG. 3A, is to edge-bondthe wood slats (12) obtained in step a) in order to form a large panel(16) of predetermined width. It is worth mentioning that during theedge-bonding step, it may be advantageous to orient the wood fibers ofthe slats, in an “inverse-manner”, that is to say that between adjunctslats, the fibers are not disposed in the same orientation, as shown inFIG. 3A. Such a disposition of the fibers will provide a betterdistribution of the internal forces.

[0044] As apparent to any person skilled in that art and in order tooptimise the bonding, the edges of the wood slats (12) are preferablyplaned off prior to bonding. Then, the large panel (16) is cutlengthwise to form a plurality of smaller panels (18) of substantiallyidentical width (w), as shown in FIG. 3B. As can be appreciated, onlyone of such small panels (18) is shown in FIG. 3B. In order to optimallyobtain the panels (18), the edge-bonding and cutting of step b) arepreferably performed in continuous.

[0045] It is worth mentioning that according to another preferredversion of the process, the small panels (18) of identical width (w) mayalso be obtained by simply edge-bonding a specific number of wood slats(12) so to obtain a plurality of small panels (18) of identical width.In this way, the step of cutting lengthwise a large panel at equallyspace apart distance so to form a plurality of small panels of identicalwidth is omitted.

[0046] As the large panel (16) and the small panels (18) both followfrom the edge-bonding of the wood slats (12) shown in FIG. 2C, theirthickness (t) and length (I) are the same as the wood slats (12), thatis a thickness (t) varying approximately betweeen 0.75 to 2 inches and alength (I) varying between 3 to 20 feet.

[0047] All the small panels (18) obtained in the process, either bycutting lengthwise the large panel (16) or by edge-bonding a specificnumber of wood slats (12) as mentioned before, have an identical width(w) which preferably varies between 4 to 16 inches. For example, forobtaining a plurality of small panels (18) of 4 inches, the large panel(16) is cut lengthwise at approximately every four inches.

[0048] It is also worth noting that in order to obtain a longer panel(18), it may be advantageous to end-joint the small panels (18) to formlonger panels, preferably up to 120 feet in length, preferably byfinger-jointing the smaller panels (18), as shown in FIG. 4.

[0049] Turning now to FIG. 5, and as already explained, the smallerpanels (18) obtained in step c) are subjected to a lamellation processwhere they are face-bonded to form a lamellated beam (20) which shows,after being rotated from an angle of 90° and as shown in FIG. 6A, athickness (t′) equals to the width (w) of the smaller panels (18) sincethe lamellated beam (20) comes from the lamellation of those smallpanels (18) and a width (w′) equals to the number of small panel (18)used in the face-bonding multiplied by the thickness (t) of the same. Ingeneral, the width (w′) of the lamellated beam (20) varies approximatelybetween 4 to 6 inches. And obviously, the length (I′) of the lamellatedbeam will be equal to the length (I) of the small panels (18) and thuspreferably varies between 3 to 120 inches.

[0050] For example, if the smaller panels (18) used has a width (w) of 5inches and a thickness (t) of one inch, and twelve of those smallerpanels (18) are face-bonded to form a large beam (20), this large beam(20) will have a thickness (t′) of 5 inches and a width (w′) equals to12 inches obtained by multiplying twelve by one inch.

[0051] Now referring back to FIGS. 6A and 6B, the lamellated beam (20)is then cut lengthwise and thicknesswise into small beams (22), only oneof which is illustrated in FIG. 6B. In other words, the lamellated beam(20) is cut along an axis pararallel to the lamellation planes (30) ofthe beam (20). which lamellation planes (30) extend at the junction ofeach two bonded faces of the panels (18), as best shown in FIG. 5.

[0052] Referring back to FIG. 1H and as mentioned before, the smallbeams (22) after being rotated from a 90° angle all shows a width (w′″)equal to the width (w) of the small panels (18) and a thickness (t″)which is directly dependent on where the large beam (20) has been cutlengthwise.

[0053] For example, if we are taking back the above example where alarge beam (20) of twelve (12) inches in width (w′) and of five (5)inches in thickness (t′) was formed, and we are cutting the samelenghtwise at each 3 inches, or in other words we are cutting the samealong different axes parallel to the lamellations planes (30) of thebeam (20) and spaced-apart from a 3-inch distance, the small beams (22)that will be obtained will have, after being rotated, a width (w) offive (5) inches and a thickness (t) of three (3) inches.

[0054] The small beams (22) are then cut lenghtwise and thicknesswise,as shown in FIG. 1H, to form a plurality of lamellated final products(10). In other words, the small beams (22) are cut along axesperpendicular to the lamellations planes (30) described above.

[0055] Referring back to FIG. 1I, the thickness (t′″) of the finallamellated wood product (10), which directly depends on where the smallbeams (22) have been cut, preferably varies between {fraction (7/16)} to16.00 inches, the width (w″), which is equal to the thickness (t″) ofthe small beams (22) of FIG. 1H, preferably varies between 4.00 to 60.00inches and the length (I) preferably varies between 3.00 to 120.00 feet.As can be appreciated in FIG. 1I, such a final lamellated wood productmay be a lamellated wood plank. As apparent to one skilled in the art, alamellated wood beam or any other type of product could also be obtainedby simply cutting the small beam (22) in thicker slices.

[0056] It should be understood that a wood slat (12), a large panel(16), a small panel (18), a lamellated beam (20) and a lamellated woodproduct (10) according to the present invention may have otherdimensions than those mentioned above without departing from the scopeof the present invention.

[0057] Prior to step c) of face-bonding, the faces of the panels (18)are preferably planed off. Likewise, after step e), edges and faces ofthe lamellated wood product (10) are preferably planed off.

[0058] It will be understood that the present invention contemplatesemploying lamelas (14) and slats (12) which come from a coniferous orbroad-leaved tree. It may also be advantageous to provide wood slats(12) made with lamellas (14) from a coniferous tree and lamellas from abroad-leaved tree. Most preferably, the final wood product (10) iscomposed of a plurality of pieces of wood coming from different speciesof trees.

[0059] As apparent to any person skilled in the art, the glue used forthe edge-bonding and face-bonding steps is any type of glue commonlyused in the field. However, the chosen glue is preferably a structuralwood glue and may be selected from among pure resorcinol andphenol-resorcinol-formaldehyde (PRF) or it may be a non structural woodglue selected from among polyvinyl acetate (PVA), urea melamine (UM) orurea formaldehyde.

[0060] The edge-bonding and face-bonding steps may be performed eithermechanically or chemically. In the case where mechanical bonding isused, the following glue will preferably be used: phenol-resorcinol ormelamine. In the case where chemical bonding is used, the following gluewill preferably be used: polyurethane or isocyanate.

EXAMPLE

[0061] The sequence of steps for making a lamellated wood product (10)according to a process of the present invention using a glue-woodassembly by mechanical or chemical bonding from the reception of the rawmaterial to the final product may be the following:

[0062] drying of the raw material which consists of a plurality oflamellas (14) to a humidity content varying between 8 to 14% by weight;

[0063] analysis of the humidity content of the lamellas (14);

[0064] if necessary, visual analysis or scanning of the lamellas todetect any defect present in each lamellas (14);

[0065] eliminating most or all the defects detected;

[0066] profiling the end joints;

[0067] if necessary, preheating the end joints for mechanical bonding orhumidifying the end joints for chemical bonding;

[0068] applying the glue on the end joints;

[0069] end jointing the lamellas (14) and pressing the joints to form awood slat (12);

[0070] hardening of the glue joints;

[0071] planing off of the wood slats (12);

[0072] if necessary, preheating the edges of the wood slats (12) formechanical bonding or humidifying the edges for chemical bonding;

[0073] applying the glue on the edges;

[0074] edge-bonding the wood slats (12) to form the large panel (16);

[0075] cutting the large panel (16) to form smaller panels (18);

[0076] profiling the end joints of the panels (18);

[0077] if necessary, preheating the end joints for mechanical bonding orhumidifying the end joints for chemical bonding;

[0078] applying the glue on the end joints;

[0079] end jointing the panels (18) and pressing the joints to form alonger panel;

[0080] hardening of the glue joints;

[0081] planing off of the panels (18);

[0082] if necessary, preheating faces of the panels (18) for mechanicalbonding or humidifying the faces for chemical bonding;

[0083] applying the glue on the faces;

[0084] face-bonding the panels (18) to form a lamellated beam (20);

[0085] hardening of the glue joints;

[0086] cutting the lamellated beam (20) along axes parallel to thelamellations planes (30) to form small beams (22);

[0087] cutting the small beams (22) along axes perpendicular to thelamellation planes (30) to form a lamellated wood product 10 of desireddimensions;

[0088] planing off and, if nesessary, treating the lamellated woodproduct (10);

[0089] visual, mechanical and physical control of the quality of thefinal product (10);

[0090] trimming ends of the final product (10) with precision;

[0091] piling and wrapping of the final product (10);

[0092] stocking the final product (10); and

[0093] shipping the final product (10) to the client.

[0094] By treating the lamellated wood product (10), it is meant toapply a product, which is preferably rubber-based or any other productknown by a person skilled in the field of wood to protect the surfacesand/or the interior of the lamellated wood product against shocks,vibrations, heat and cold temperature, differences in temperature,humidity, larvae and insects, etc. . . .

[0095] Therefore, a lamellated wood product (10) according to thepresent invention may have many different uses. For example, it may beused as a composing element of a railroad, as a composite element of ahouse, a furniture or a decorative moulding, as a composing element of awharf, as a composing element of an electric or a telephone post.

[0096] Although preferred embodiments of the present invention have beendescribed in detail herein and illustrated in the accompanying drawings,it is to be understood that the invention is not limited to theseprecise embodiments and that various changes and modifications may beeffected therein without departing from the scope or spirit of thepresent invention.

What is claimed is:
 1. Process for making a lamellated wood product,comprising the steps of: a) providing wood slats of generally uniformthickness; b) edge-bonding the wood slats to form a large panel of apredetermined width; c) cutting lengthwise the panel of step b) into aplurality of small panels of substantially identical width; d)face-bonding a number of the small panels to form a lamellated beamhaving a thickness equal to the width of the small panels and a widthequal to the product obtained by multiplying said number of small panelswith the thickness of the same; e) cutting lengthwise and thicknesswisethe lamellated beam into a plurality of small beams having a widthidentical to the width of the small panels; f) cutting lengthwise andthicknesswise the small beams into a plurality of lamellated woodproducts of desired dimensions.
 2. Process according to claim 1, whereinthe wood slats are end-jointed lamellas.
 3. Process according to claim2, comprising prior to step a), a step of providing lamellas ofgenerally uniform thickness and end-jointing the lamellas to form thewood slats of step a).
 4. Process according to claim 1, wherein prior tostep b), edges of the wood slats are planed off.
 5. Process according toclaim 1, wherein the edge-bonding of step b) and the cutting of step c)are performed in continuous.
 6. Process according to claim 1, whereinprior to step c), a step of end-jointing the small panels to form longerpanels.
 7. Process according to claim 1, wherein prior to step d), facesof the small panels are planed off.
 8. Process according to claim 1,wherein after step f), edges and faces of the lamellated wood productare planed off.
 9. Process according to claim 1, wherein the wood slatscome from a tree selected from the group consisting of a coniferous treeand a broad-leaved tree.
 10. A lamellated wood product obtained by theprocess as claimed in claim
 1. 11. Process for making a lamellated woodproduct, comprising the steps of: a) providing wood slats of generallyuniform thickness; b) edge-bonding the wood slats to form panels of agiven width; c) face-bonding the panels to form a lamellated beam with aplurality of lamellation planes; d) cutting the lamellated beam along anaxis parallel to the lamellation planes to form small beams; e) cuttingthe small beams along at least one axis perpendicular to the lamellationplanes to form a lamellated wood product of desired dimensions. 12.Process according to claim 11, wherein the wood slats are end-jointedlamellas.
 13. Process according to claim 12, comprising prior to stepa), a step of providing lamellas of generally uniform thickness andend-jointing the lamellas to form the wood slats of step a).
 14. Processaccording to claim 11, wherein prior to step b), edges of the wood slatsare planed off.
 15. Process according to claim 11, wherein in step b),the wood slats are edge-bonded then cut lengthwise to form the panels.16. Process according to claim 15, wherein the edge-bonding and cuttingof step b) are performed in continuous.
 17. Process according to claim11, wherein prior to step c), a step of end-jointing the panels to formlonger panels.
 18. Process according to claim 11, wherein prior to stepc), faces of the panels are planed off.
 19. Process according to claim11, wherein after step e), edges and faces of the lamellated woodproduct are planed off.
 20. Process according to claim 11, wherein thewood slats come from a tree selected from the group consisting of aconiferous tree and a broad-leaved tree.
 21. A lamellated wood productobtained by the process as claimed in claim
 11. 22. Process according toclaim 8 or 19, wherein the lamellated wood product is treated with arubber-based product.